The present invention relates to links for continuous chains and more particularly to links of chains utilized to convey or "drag" particulate material.
Continuous chains formed of links having U-shaped frames and consequently openings in the interiors thereof have long been used to convey, commonly known as "drag", particulate material of sizes ranging from finely divided to briquetted solids. In all such applications, particularly in industrial applications where chain conveyor operation is over extended intermitent or continuous periods, wear on the chain link units is a significant problem due to abrasion between conveyed particles and the links. Wear problems are aggravated in instances, such as in foundries, where it is required that the links convey particulate material through environments of widely differing temperatures, including those ranging from normal atmospheric ambient conditions to elevated temperatures ranging up to and over 400.degree. C.
Due to such wear problems, it is imperative in utilization of any chain conveyor system that the system periodically be shut down to remove deteriorated, worn and/or broken links of the conveyor chain with an attendant increase in equipment investment expenditures and operating costs due to the expenses of the replacement link units, losses in production time and incurrance of repair labor time. Expenditure losses in terms of lost production time and repair labor often are particularly acute when a conveyor chain system is interrupted due to link breakage. In many such cases the broken link is positioned in the path of the chain where it is only accessible with difficulty. In any event, link replacement effects are hampered, due to the designs of conventional conveyor link chains in which connecting pintles for successive link units are held in place by means of locking pins and the like, and problems are encountered in properly positioning the involved link units to align the slots, etc., of the separate elements of the to-be-connected units to allow operative placement of the locking pins.
To attempt to minimize wear problems in chain conveyor systems it has been proposed to construct the links thereof from expensive specifically selected alloys. In many cases, such as with chain conveyor systems employed in foundry operations, the use of special alloys for the chain links has not proved to be completely suitable due initially to the requisite increased equipment expenditure and due to the fact that many alloys available still develop pin holes and/or wear unevenly and/or even prematurely fracture stemming from imperfections in the alloy material introduced in one or more of the alloying, molding, heat treating and/or quenching steps involved in producing the links. Another suggested approach to minimize such wear problems has involved the application to some or all of the link surfaces of a coating of an abrasion-resistant material such as is formed by fusing welding electrode material to the link surfaces desired to be protected. This approach, however, while it has achieved some success in extending service life of some links, has still suffered drawbacks in use due to the aforedescribed problems of costly delays in achieving alignment of conventional locking elements when chain dissassembly for repair is necessary.
Accordingly, a search has continued in the art for an improved link for continuous conveyor chains which is relatively inexpensive, has extended wear life, and is readily adapted for assembly into and disassembly from a chain system.